Gauge valve



FIG. 1 is a front elevational view of a gauge valve showing my new design.

FIG. 2 is a rear elevational view thereof.

FIG. 3 is a top plan view thereof.

FIG. 4 is a bottom plan view thereof.

FIG. 5 is a left side elevational view thereof.

FIG. 6 is a right side elevational view thereof. 

The ornamental design for a gauge valve, substantially as shown. 